package com.google.code.springwt.client.pattern;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/**
 * Base class to implement pattern "Supervising Controller". The "view" is required to be Observale so that the
 * controller can register as a listener to events.
 * <p>
 * Derived class must implement the <code>on(Event)</code> method to handle the events fired by the supervised view. A
 * recommended use is to define in the view interface an enumeration of event types, so that the controller can use a
 * simple <code>switch</code> to select the adequate method to invoke :
 * 
 * <pre>
 *    public void on( Event&lt;MyWidget&gt; event )
 *   {
 *       switch ( (MyWidget.Events) event.getType() )
 *       {
 *           case VALIDATE:
 *               onValidate()
 *               break;
 *           case CANCEL:
 *               onCancel()
 *               break;
 *       }
 *   }
 * </pre>
 * 
 * @see http://martinfowler.com/eaaDev/SupervisingPresenter.html
 * @author ndeloof
 */
public abstract class SupervisingController<T extends Observable<T>>
    implements Listener<Event<T>>
{
    protected T view;

    public abstract Object getModel();

    public void setView( T view )
    {
        this.view = view;
        view.addListerner( this );
    }
}
